Bio-efficacy and residue of different insecticides against leaf miner, Phyllocnistis citrella Stainton and citrus butterfly, Papilio demoleus Linnaeus in/on Kinnow mandarin

The bio-efficacy of different insecticides against leaf miner, Phyllocnistis citrella Stainton indicated that the lowest leaf damage percentage was observed in the treatment of spinosad 45 SC followed by imidacloprid 17.8 SL and thiamethoxam 25 WG, i.e., 5.46 to 4.78%, 7.73 to 5.35% and 8.28 to 6.23%. In contrast, malathion 50 EC and Bacillus thuringiensis var. kurstaki were found to be the least effective after the first and second sprays. The lowest larval population of P. demoleus was found in quinalphos 25EC @ 175 g a.i/ha, followed by chlorpyriphos 20EC @ 350 g a.i/ha, i.e., 5.50 to 1.83 larvae/plant and 6.42 to 3.42 larvae/plant. In contrast, the maximum larval population was recorded in nimbecidine 0.03% @ 3 ml/l but better than the control during both seasons. The residues of malathion (625 and 1250 g a.i. ha-1), imidacloprid (17.8 and 35.6 g a.i. ha-1) and thiamethoxam (25 and 50 g a.i. ha-1) in Kinnow juice were determined at different time intervals, i.e., 0 (Two hours after spray), 1, 3, 5, 7, 10, 15 and 30 days after first and second spray. The average residues of malathion (0.012 and 0.025 µg g-1), imidacloprid (0.12 and 0.19 µg g-1), and thiamethoxam (0.07 and 0.1 µg g-1) at both doses in Kinnow juice found below MRL on 0 day. The half-life values at single and double doses were 4.2 and 5.2 days for malathion, 3.47 and 3.71 days for imidacloprid, and 3.6 and 4.2 days for thiamethoxam.